The service life of a light-emitting element such as a light-emitting diode decreases as temperature increases. Accordingly, there is a demand for a light source incorporating a light-emitting diode to be able to efficiently extract and externally output light from the light-emitting diode while suppressing an increase in temperature of the light-emitting diode.
To meet the demand, there is a conventional light-emitting device using a white ceramic substrate as a substrate on which a light-emitting diode is mounted. The ceramic substrate is fixed to the body of the light-emitting device by a securing member such as a screw. The body is made of a metallic material having excellent thermal radiation performance, such as aluminum.
The ceramic substrate is characterized by being more fragile and more easily cracked than a metal substrate. Therefore, when the ceramic substrate is fixed to the body of the light-emitting device by screws, the ceramic substrate sometimes breaks.
Further, a difference in coefficient of thermal expansion between the ceramic substrate and the body inevitably causes stress to act on a portion of the ceramic substrate which is fixed to the body. As a result, the ceramic substrate is sometimes damaged during operation of the light-emitting device.